Messages in this thread | | | Date | Wed, 18 Jan 2023 11:51:23 +0100 | Subject | Re: [PATCH v2 00/21] blksnap - block devices snapshots module | From | Hannes Reinecke <> |
| |
On 1/17/23 22:04, Mike Snitzer wrote: > On Fri, Dec 09 2022 at 9:23P -0500, > Sergei Shtepa <sergei.shtepa@veeam.com> wrote: > >> Hi Jens. Hi Jonathan. Hi all. >> >> I am happy to offer a modified version of the Block Devices Snapshots >> Module. It allows to create non-persistent snapshots of any block devices. >> The main purpose of such snapshots is to provide backups of block devices. >> See more in Documentation/block/blksnap.rst. >> >> The Block Device Filtering Mechanism is added to the block layer. This >> allows to attach and detach block device filters to the block layer. >> Filters allow to extend the functionality of the block layer. >> See more in Documentation/block/blkfilter.rst. >> >> A tool, a library for working with blksnap and tests can be found at >> www.github.com/veeam/blksnap. >> >> The first version was suggested at 13 June 2022. Many thanks to >> Christoph Hellwig and Randy Dunlap for the review of that version. >> >> Changes: >> - Forgotten "static" declarations have been added. >> - The text of the comments has been corrected. >> - It is possible to connect only one filter, since there are no others in >> upstream. >> - Do not have additional locks for attach/detach filter. >> - blksnap.h moved to include/uapi/. >> - #pragma once and commented code removed. >> - uuid_t removed from user API. >> - Removed default values for module parameters from the configuration file. >> - The debugging code for tracking memory leaks has been removed. >> - Simplified Makefile. >> - Optimized work with large memory buffers, CBT tables are now in virtual >> memory. >> - The allocation code of minor numbers has been optimized. >> - The implementation of the snapshot image block device has been >> simplified, now it is a bio-based block device. >> - Removed initialization of global variables with null values. >> - Only one bio is used to copy one chunk. >> - Checked on ppc64le. >> >> The v1 version was suggested at 2 November 2022. Many thanks to Fabio >> Fantoni for his for his participation in the "blksnap" project on github >> and Jonathan Corbet for his article https://lwn.net/Articles/914031/. >> Thanks to the impartial kernel test robot. >> >> Changes: >> - Added documentation for Block Device Filtering Mechanism. >> - Added documentation for Block Devices Snapshots Module (blksnap). >> - The MAINTAINERS file has been updated. >> - Optimized queue code for snapshot images. >> - Fixed comments, log messages and code for better readability. > > [this reply got long...] > [ .. ] > > But you've already bypassed me, my hope is that Jens and Christoph > agree that we need this line of development to be in service to other > areas of the Linux block subsystem and its drivers that were > established for the purposes of remapping IO. It cannot just be > the subset needed to cement veeam's ability to use Linux for its > purposes (but I completely understand that is the point of veeam's > exercise). > That's why I proposed my topic at LSF/MM, precisely to figure out how to handle these issues.
Cheers,
Hannes
| |